When and How to Reset Mac SMC (System Management Controller)

“Ahhhh my Mac isn’t working! I need to reset the SMC!” You have tried rebooting, you’ve reset the PRAM, you’ve done it all, but your Mac is still behaving strangely. What next? In certain circumstances, resetting your Mac System Management Controller (SMC) can be a solution. This is sometimes necessary to restore normal lower level system functionality to your Mac, particularly for power and hardware related troubles.

We’ll show you exactly how to reset the SMC on any type of Mac (and any version of OS X) and the type of problems that it may resolve.

When & Why Reset SMC on a Mac? Some Common Hardware Reasons

Typically, an SMC reset helps to resolve many power and hardware related issues that are otherwise unresponsive to troubleshooting techniques. Resetting a Mac SMC is particularly effective if you’re having the following types of problems:

* Issues with your Mac cooling fans and fan management: the fans run constantly at high speed, fans run high despite low CPU usage and adequate ventilation, fans not working at all, etc

If those type of issues describe the problem encountered on the Mac and you have concluded that you need to reset your SMC, we will show you how to do it on any MacBook, MacBook Pro, MacBook Pro with Retina display, iMac, Mac Mini, and Mac Pro. Do notice that the System Management Controller reset instructions are different for MacBook and MacBook Pro’s if the machine has an internal battery versus a detachable battery, additionally the procedure is different for desktop Macs than from Mac laptops.

This is how to reset SMC on most modern Mac laptops, none of which have a removable battery:

Shutdown your MacBook Air / MacBook Pro

Connect the power adapter to the Mac

On the MacBook / Pro’s keyboard, hold down the Shift+Control+Option keys and the Power button at the same time

Release all keys and the power button at the same time – the little light on the MagSafe adapter may change colors briefly to indicate the SMC has reset

Boot your Mac as usual

Here’s the key sequence to hold down:

Do keep in mind that by resetting the SMC you will lose power specific settings, like the time it takes to sleep a Mac and other customizations to power settings. No big deal, but if you have made many changes to your hardware behavior you will want to adjust stuff like sleep behavior again.

The boot time after resetting a machines SMC can be a bit longer than usual, that is normal.

Reset SMC of an iMac, Mac Pro, Mac Mini

Resetting SMC is different for non-portable Macs, but it’s still easy enough and the problems it addresses are the same. On any desktop Mac, here is how you reset the System Management Controller:

Shut down your Mac

Disconnect the power cord

Press and hold the Mac’s power button for 5 seconds

Release the button

Reattach the power cables and boot the Mac as usual

Reset the SMC of a MacBook or MacBook Pro’s with detachable batteries

Older MacBook laptops, indicated by having a removable battery, can reset SMC with the following approach:

Shutdown the MacBook/Pro and remove the battery

Disconnect the power adapter, hold the Power Key for 10 seconds

Release the power key and reconnect your battery and power adapter

Turn your Mac on

Let boot as usual

What is SMC anyway?

SMC stands for System Management Controller, a critical low-level component on Mac hardware. Much like the name sounds, the SMC controls and managements system hardware for power consumption, battery charging and battery function, thermal activity and fan activity, LED lighting for keyboards and displays, GPU functionality with video mode changes and video output, sleep and wake, and other core hardware functionality on a Mac.

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Now that your Mac SMC has been reset, the hardware issue you were encountering should be resolved, unless there is a greater problem or a different issue that needs to be troubleshooted separately. Sometimes resetting the Macs PRAM can be effective too, though there are times when further action is necessary as well. Do note that only Intel Macs have an SMC controller.

Hopefully that will clear up your problems, if not it might be worth a visit to the Apple Store or a certified repair center.

124 Comments

[…] If all else fails, try this, which has worked for some individuals: * Reset your Mac’s System Management Controller (SMC) : Shutdown the MacBook/Pro, remove the battery, disconnect the power, hold the Power Key for 15 seconds. Replace the battery, reconnect power, and zap PRAM and wait for 2 chimes before letting the keys go. Check out more information on when and how to reset your SMC. […]

[…] the error message anyway, the message was cleared and everything went back to normal after the SMC power management controller was reset. Anytime your Mac has power management type issues it’s worth giving the SMC reset a shot, it […]

OS Lion is destroying Mac Book Pro batteries. Not only is battery life diminished by about 50% but the extra load on the battery is killing the battery itself. Apple is doing their best to deny replacing the ruined batteries but at some point the pressure from customers will make them face this issue, or litigation will.

I have a macbook pro 17 inch running Yosemite for awhile everything ok. Today screen goes black can’t see anything and I try to type but the macbook does not recognize my laptop keyboard? When I try the pram doesn’t work tried everything!!!!
HELP ME!!!

[…] I’ve gotten in the habit of immediately putting my MacBook Air to sleep by shutting the lid, by far the easiest method if you’re on the go. Typically this works without a hitch, but today the Air didn’t sleep when shut. Because the MacBook Air has no moving hard drive or sleep light, I didn’t notice this until I went to use it again about two hours later when I found the machine to be unusually hot to the touch because it never slept as intended. From there on it became a repeatable occurrence, and while I’m not sure of the cause, the solution was just a matter of resetting the SMC: […]

Thank you so much. I did lots of searching to find the answer to my problem (fan running, no keyboard or monitor functionality – external keyboard didn’t work either – and you laid out the answer so clearly and simply and it WORKS! MacBook 1,1 Intel Core Duo

Ok so I have a MacBook (white) and I’ve tried doing this. I’ve had the same problem as the wont sleep thing, but for about a week. Yesterday, I was about to go to the Apple store and try to fix it, but I got it working last minute and didn’t go in. Well, I started getting these restart messages every time my computer did start working, and had to keep doing this until the computer just gets stuck at the white loading screen with a grey spinning wheel under an apple sign(grey) also, this computer has the rounded edges and no, does not have the removable battery. Help!!!!!!!!!

My mac book pro doesn’t wanna switch on, I have to flush my SMC, please help, it did this once cause of something I plugged in, got it fixed at a hefty price, but they didn’t really change any part so it should be something I can change myself…

I’m trying to reset the SMC on my MacBookPro 17″ 2010 because, as many others I’m having all sort of problems since when I updated my system to damn Mavericks!

How long do I have to hold shift+ctr+opt+power buttons down? I tried to just push them, I tried to hold them down for a little while… how do i understand that the SMC has indeed been reseted? A beep? A light? Any sign at all?

Thx a lot for this manual.
I was running FileVault to save my files, but because I had wrong rights filevault terminates my Mac, so that it freezes and nothing more was working. After a hard reset and after trying to reboot from the recovery it only came the internet recovery option. Nearly on the way to the Apple store. Could be that the hard drive is dead. I read your explanation of the smc reset. I tried, because it was my last chance. Done and rebooted into the recovery section with the harddiskrepair. Checked the harddisk…seems okay, but the rights are wrong. Trying now to fix the issue and maybe then I will have the chance to unlock the data. I will see, because decrypted not really much. Maybe I have a chance. But without your help I will be now at the Apple store and bought me a new hard drive or ship it to the care center. Thx from Germany !!! You saved my day. Trying to get help the whole night without any sleep and now it’s high noon

I’m having problems with my MacBook Pro-2011, with an SSD and running Lion.
I reset the SMC twice in the last two weeks because the laptop works fine for a little while after doing it. But after using it for a few days, it gets weird again. It starts with the fans running very high when charging the battery and it could just turn off suddenly at any moment.
Any ideas? Do I have to keep resetting the SMC once a week?
Great website, by the way. Thanks!

Awesome! My MacBook Pro was booting to black screen. Last time it happened it was a PRAM reset boot that seemed to “fix” it. But this time it was this trick. For people not understanding the instructions, you press those buttons, and yes, there is no feedback!-P but you just press power alone afterwards to reboot. This time no black screen. What is this actually doing?!?!?!!!!!

i have a macbook air, recently got a mini display port to connect to my tv via hdmi. ever since i connected it my tv picture is now flashing on and off but sound stays constant. when i disconnect and try and play my ps3 its still flashing. tv was fine before i tried connecting my mac. I’ve gotten it to work twice but then it stops again. when i try reset smc it works for a couple of seconds then flashes again

my iMac 24″ mid 2009 last October 2013 would not power up just a black screen & 3 beeps that would repeat after a few seconds. I put it in the box until March 2014 then took it to Apple Store where it powered on to my surprise. It worked until May & the same unable to power up happened. Tried off & on for two months but still a black screen with the beeps. I saw your article yesterday morning & tried it as the power cord had not been plugged in I removed it from the back of the iMac & followed your instructions. It powered right up where it left off back in May. Thank you very much for the info. It took the rest of the day to do all the updates through installation of lattest operating system Yosemite. Again thanks😃

Thank you for helping me out. My fans were running constantly and Bluetooth hardware could not be found. Did as instructed on my iMac and it is magically back to normal. Whew! Thought I was going to have to carry my machine 150 miles to the nearest service center. I am so happy this worked. Thank you.

I did the SMC reset on my Macbook Pro (late 2013) and it worked for me. This morning, I put my mac to sleep and the screen stayed black despite hearing the startup bell.
I followed the instruction (pressed the 4 keys together for a few second, then released them together, before pressing the Power button on the top right and like magic, the screen was back on.

My Macbook pro 2010 cant even show a black or blue screen, no beep, it seems completely dead. It can only show a green light on the charger and can blink green on the machine if I remove the charger. That is the only life it seems to have. I ve tried to reset the SMC and the PRAM nothing can work. Please help

Done SMC half a dozen times with and without power cord as well as holding the buttons down for 10 sec, reset Pram, done a restore, till I’m blue in the face. The MacBook air 11 inch (2010) still runs terribly slow. The symptoms certainly seem to point to SMC but doing the reset as mentioned above does not work. Is there any other way to reset it?

my old but goodie IMac 20″ boots to black screen it “works” fine but the display stay black .. only way it comes on if i put it into sleep mode then when i wake it up i see the desktop running fine but the display Only flash on for a brief second and i can’t do nothing. It flash off again (black screen again) i tried resetting the SMC and also the PRAM the black screen remains.? Anybody got a solution?

White macbook A1181 standby light on the right hand side of the trackpad comes on and stays on, but no display no chime..bottom of the laptop heats up a bit after making a couple of attempts to power up. Tried resetting smc, that didn’t work either. Can someone help as what the problem could be ?

Hey, I have an old (7 or 8 years?) Macbook that’s developed all kinds of quirky issues like staying awake when the lid is closed, esp. if connected to the power cord, the fan occasionally running like crazy, and internet connection problems. These include just dropping the connection (I check with my kids and it’s always working fine for them) and not being able to get more than 15 feet from my router and remain connected.

I tried resetting the SMC and the sleep and fan issues haven’t reoccurred. So, yay! However, the internet connectivity problem is still there; at least the part where I have to be in the room with the router. I’ll try resetting PRAM; however I suspect it’s just a hardware degradation problem.

Also, I love that this article was written more than five years ago and continues to be of help! Thanks!

About your wifi problem with your Macbook, it may be the wifi router and not the Macbook. I had an older D-Link wifi router bought from Best Buy, and the signal was sometimes weak and I too could not be more than 15 feet away to get a strong signal.

Finally, I went to a specialty electronic shop and bought a more powerful wifi unit (dual diversity with two antennaes) and that fixed the poor reception problem. Sorry. not at my home office, so I can’t tell you the model of my new wifi unit.

Also the newer units have a higher gigabyte trabsfer rate than the older units, so if your is more the three years old, best to replace it.

Thanks for this info,Mac Book Pro Retina took a pretty hard dive off of front seat of truck tucked in a soft carry bag due to having to slam on the brakes for a car that stopped abruptly in front of me(no accident but front seat valuables took a dive to the floorboard) when I got home and powered up the Mac I had a bluish screen with no control or visuals. I tried a few different things and after almost resigning myself to a trip to the Apple Store I ran across this (two hours into it) and voila up and running. Awesome Info

I have an old 2007 MacBook Pro I call “Old Faithful”. I purchased it used. I’ve been using it for two years non-stop with Adobe Pro Suite. It has always run firey hot. I only have 4GB RAM and have to use an app to frequently free the RAM if using Safari (which ALWAYS uses about 1.5GB RAM to my dismay….grrrrr) The entire two years the fan always runs like a monster after about an hour’s use….even when here is plenty of RAM available (like 1.8GB) and only one app open like Finder or TextEdit or MS Word. I’ve often had the issue where the screen won’t come on after lid-closing-sleep mode over the past two years and just hard rebooted to get it back.

Yesterday it decided to remain black permanently. It boots fine and I can tell by the sounds that it makes it to the login screen, but the HD continues to run and do various things by the sound of it which is weird. I took out the battery And it looks semi-exploded with a big bump on the outer side and a gap at one corner. Yikes – I wonder how long it’s been that way! LOL. I tried to run the MacBook without the battery installed using only the power adapter, but it boots without display still. I tried resetting SMC with and without battery. No help. I reset PRAM with/without battery, no help.

I have a new battery arriving today from Amazon. I’m going to try the alternate SMC reset for non-removable batteries first, entering my password at the login screen, and the newly discovered keystroke sequence for putting it to sleep. Ill try all three again with new battery. I’ll report back of my results.

My “hunch” is if these don’t work either, given the intense heat this MacBook Pro runs at, I may be looking at a heat damaged video graphics card???

I learned this the hard way (resetting the SMC) by waiting for an appointment at the Genius Bar. Now, one month later, same problem and your website reminded me what to do. Question: why is this happening? One month after the first time. Thanks so much!

Ehmm… did any of you ever notice that following the SMC-procedure on Mountain Lion leads straight into your Mac-user account, even if it is password restricted? If so, this is possibly a great by-pass for hackers who’ve gotten hold of you Macbook into your personal data.

This is a really helpful website – and thread! Judy what happened with the new battery?

I also have an ‘old faithful’ 2008 white removable battery macbook which has black screen issues. It flashes up on starting though. My hot corner shortcut (which sends it to sleep) also seems to have some affect, temporarily flashing up (on waking) so I know the screen works.

My battery got really swollen a year ago so I just took it out and only use it plugged in now… so have tried both these SMC & PRAM shortcuts/resets.

Using my projector to see what I was doing had the miraculous effect of bringing the macbook screen back to life, yay!
But then… After 3 hours it just went off again (I was using Safari and had just opened photoshop).

I’m going to order a new battery and see if that regulates the power and fixes the problem. If I don’t write again- it worked. :) (hope that’s what Judy did!).

Well, no it didn’t fix it. My MBP (17″ pre-unibody Intel) starts to load the system, gets about 1/4 to 1/3 way through, stutters then shuts down. Tried resetting SMC, PRAM, but still the same. Doesn’t work booting from an external SDD either.

So absolutely none of these worked. I tried to do updates on my computer and it said that the computer would restart. It tried to restart but when it loaded halfway it went to a black screen with a spinning wheel. The wheel would go away for about 3 seconds and come back over and over again. I’ve tried every diagnostic I could find on the Internet including everything on here. Nothing is working

Hey, i think i have some particular issue that may be different from other people here. Btw, thanks for the tips as i see many people happy now. I never had problems with my Macbook pro late 2011, but two days ago using a viewer to second life, as i use it since i bought the pc, when the fan start working hardly as the viewer always pushes a bit from the graphics, the monitor turned black, i still hear sounds, the macbook is still working but black. Then i tried to do the 3thd option that was advised but nothing as i tried to run the viewer and as soon as fan started to be heard the monitor turned black again..I will try the smc but i don’t know.. i do not find here people with same issue… any helps ? I’m using last el capitan, could be a bug from the OS ? hope..so.. Thanks

I am so thankful for your tutorial I didn’t know what I was going to do. I thought I may have replace my IMac. I thought rebooting but you never know thanks again!!!! Love the Internet for help on what seems hard is so simple.

Nothing worked for me. Tried all of it and still trying to connect note 5 with imac, it says connected for a few seconds then says not connected. I don’t know what else to do? Any suggestions would be appreciated..

MBP 2009 17 INCH replaced battery, charged it up to 100% pulled power cord, computer shuts down about 1 minute later. It was doing this before I replaced the battery! Battery shows it is ok. carried out SMC no change. Conditioning of battery not able to be done because of unit shutting down all the time.
Any suggestions?

Nope, macbook pro is still a black screen. I can see the keyboard backlights dim or illuminate to the keyboard keys, the caps lock light toggles green. The screen brightness isn’t changing while I press the brighter button. I can see a faint change in the screen when it’s off vs on. I removed the back cover in hopes to toggle something and REALLY turn it off. But the screen remains black despite all attempts to revive/wake/whatever.

I am not an IT person – I just want my iMAC to work the same way it did before the upgrades – I don’t need the upgrades – I DO NEED THE USB ports !!!!! why can’t Apple leave things working that were working !!!!

Tried this and still nothing. I’ve replaced HDD and rams. Reset smc, PRAM and still no luck. There’s power but no Display or chime sound. Just power only. Running out of options. Anyone have any other clue as to how this can be fixed? Doesn’t allow me yo reboot from scratch either.

My USB ports are down. I reset pram and DMV and still have same problem. Notable might be that I saw no blinking or color change from the mag safe light.
I will now try the contacts, then the voltages. Then CK to google.

This error appeared after updating to the latest version of OS. Cannot fix it with the reset. I can’t connect to my iPhone at all, and it’s the iPhone giving me the error. I have been using the two in tandem forever. though it does allow the CD burner. It is a screwed software problem with Apple. I will have to go in to the Apple store. Thanks for the screw up Apple!

Plugging the power adapter on my MacBook Air charges the battery for about one minute then stops recharging. I tried the SMC reset but didn’t help. Any idea what else can be done besides trying a new adapter?

iMac don’t like the official keyboard being used with extension usb cable, as plugged in directly and other usb devices, but as soon as usb extension cable went in, stopped working.
Although, other usb ports don’t die after extension cable attached, just the fourth.

2010 13″ MacBook white. Battery says “do not remove”… Why??? I’ve tried everything else on this and other forums/sites/howtoguides, ever since my charging light won’t turn on, as well as my computer. Oh f#@%!!! So I was thinking about removing the battery, and trying powering on with only power cable. This always worked with previous PC laptops when batteries took a $#!+. What’s the worst that can happen? I got no money for those Mac “Geniuses” at the Mac “Store”. Please help. I will be forever indebted to anyone who can shed some light on this predicament. Thanks

Very old laptop here on it’s last legs, battery has had trouble for the last 9 months – used to need to be plugged in at all times, and then after a long period of being plugged in, it started to behave normally. The other night it died (at 28%) while not plugged in. Turning it back on showed the dreaded X. Did this reset and it seems to be ok now! No more X, no more fans. I think that has bought be a bit more macbook life, yay!

Mid-2010 MacBook- won’t charge with either of my chargers which both work fine with another Macbook. Charger light won’t come on in any color – can only use when plugged in, and it stays at just 1% battery while connected. Tried SMS and PRAM resets, nothing changed. Have cleaned up around prongs on charger and on computer beforehand. Assuming maybe a new battery needed? Help!